Nitrogens

Nitrogen is a chemical element with the symbol N and atomic number 7. It is a non-metal located in group 15 of the periodic table. In Earth's atmosphere it exists predominantly as diatomic nitrogen (N2), a molecule with a strong triple bond that is relatively inert at room temperature and pressure.

Although N2 is inert in the air, nitrogen is essential for life. It is a major component of amino acids, proteins, nucleic acids, and many biomolecules. Most organisms rely on fixed forms of nitrogen, produced by microbes and some abiotic processes, to assimilate into organic compounds.

The nitrogen cycle describes the conversion of nitrogen among its various chemical forms. Key steps include nitrogen fixation (N2 to ammonia, NH3), nitrification (NH3 to nitrites and nitrates), assimilation into biological molecules, ammonification, and denitrification back to N2. Nitrogen forms range from ammonia (NH3) and ammonium (NH4+), to nitrite (NO2−) and nitrate (NO3−), as well as nitrogen oxides (NOx) and nitriles, amines, nitrated compounds, and inorganic salts.

Industry and technology rely heavily on nitrogen chemistry. The Haber-Bosch process converts N2 and hydrogen into ammonia for fertilizers, enabling large-scale agriculture. Cryogenic liquid nitrogen is widely used as a coolant and in various industrial applications.

Natural isotopes of nitrogen include 14N and 15N, with 14N making up the majority of atmospheric and biological nitrogen. Environmental considerations include emissions of nitrogen oxides and the impact of fertilizer use on ecosystems through eutrophication and greenhouse gas release.